Antistatic film compositions and elements



April 8, 1969 G. F. NADEAU 3,437,484

ANTISTATIC FILM COMPOSITIONS AND ELEMENTS Filed July 26, 1965 POLYESTER -F/LM SUPPORT ANT/STATIC LAYER L/GHT SENS/T/VE SILVER HAL/OE EMULS/O-IV LAYER SUBS/N6 LAYER POLYESTER F/LM SUPPORT A/VT/STAT/O LAYER [3 Fla 3 LIGHT SEA/S/T/VE LAYER L .SUBB/NG LAYER j E POLYESTER FILM SUPPORT /4 u Z/ is as N6 LAYER ANT/STATIC LAYER GALE E NAOE'AU INVENTOR.

ATTORNEYS United States Patent Office 3,437,484 Patented Apr. 8, 1969 3,437,484 ANTISTATIC FILM COMPOSITIONS AND ELEMENTS Gale F. Nadeau, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Filed July 26, 1965, Ser. No. 474,632 Int. Cl. G03c 1/82; C08f 3/34; B44d 1/24 U.S. Cl. 9687 20 Claims This invention relates to a novel and improved antistatic coating composition. In one of its apsects, this invention relates to a novel composite, light-sensitive photographic film element comprised of a flexible polyster film support and an outer applied layer of a novel antistatic composition. In another of its aspects, this invention relates to a novel photographic element which combines excellent antistatic, blocking and ferrotype properties.

The accumulation of electrical charges on photographic film has been the source of considerable problems in the photographic art. These charges are usually produced by the friction of the film moving over rollers or past the gates of a camera, or by the separation of the emulsion from the backing side, or upon unreeling of a large roll of photographic film, or by other handling procedures, and when discharged, are manifested as irregular fogged patterns in the emulsion of the film after it has been developed. Attempts to overcome this tendency of light-sensitive photographic films to accumulate and discharge static electrical charges have generally followed the lines of applying to the film support various conducting or hygroscopic materials as antistatic layers or backings. These layers are usually comprised of a resinous vehicle or carrier and at least one electrically conducting material such, for example, as an inorganic salt. The film support with applied antistatic layer or backing is thus provided with a layer that will dissipate any accumulated electrical charges, the effectiveness thereof being dependent upon the particular conducting material and composition employed.

Film supports prepared from polyester resins such, for example, as polyethylene terephthalate have proved highly satisfactory for use in the manufacture of photographic film products. However, the use of polyester film supports has been limited to some extent owing to the fact that it has been diflicult to establish and maintain a satisfactory bond between a surface of the polyester film support and an applied antistatic layer or backing. Another factor of prime importance tending to limit the utility of polyester film supports is that, in general, the proposed antistatic layers or backings have not been found entirely satisfactory for many photographic applications from the standpoint of antistatic effectiveness or feasibility for commercial operations. For example, many of the proposed inorganic salt containing layers or backings have been found to function effectively for antistatic purposes, but still be wholly unsuited for use in polyester photographic film elements either because of poor adhesion, because of the deleterious effects of the salts on the sensitive photographic emulsion layers, or because the photographic elements containing such layers tend to block or ferrotype when stored in sheets or rolls. In addition, many of the proposed inorganic salts have had the serious shortcoming of being too hygroscopic. Such salts tend to absorb moisture causing a significant deterioration in the photographic quality of the films.

It is, accordingly, an object of this invention to provide a novel antistatic composition.

Another object of this invention is to provide a composite film element comprised of a polyester film support having thereon a layer of the above novel antistatic composition.

Another object of this invention is to provide a photographic film product comprised of the composite film element of this invention, and more particularly a polyester film support having on one side thereof a layer of a novel antistatic composition and on the opposite side of the support at least one light-sensitive silver halide emulsion layer.

Another object of this invention is to provide a photographic element having improved antistatic, blocking and ferrotype characteristics, which element has a polyester support having one surface coated with a relatively thin adjacent subbing layer comprising a vinylidene chloride, alkyl acrylate, itaconic acid copolymer and over this layer, an antistatic layer, as described herein.

Still another object of this invention is to provide a photographic element having a polyester support coated on one side with a relatively thin subbing layer of vinylidene chloride, alkyl acrylate, itaconic acid copolymer, which layer is overcoated with an antistatic layer, as described herein, and on the other surface of the polyester support, a relatively thick subbing layer of vinylidene chloride, alkyl acrylate, itaconic acid copolymer, which layer is overcoated with a light-sensitive silver halide emulsion ayer.

Still another object of this invention is to provide procedures for the preparation of novel antistatic compositiOILS and novel photographic materials prepared therewit Other objects will become apparent hereinafter.

In accordance with this invention, it has been found that markedly superior antistatic polyester photographic films can be prepared by the use of a novel antistatic coating composition comprising as conducting materials, certain metal halides (e.g., alkali metal halides such as sodium chloride, potassium chloride, etc.), a polyvinyl alcohol binder or vehicle, preferably employed in combination with a hardener therefor, and a suitable matting agent with cross section diameters of from 0.5 to 15 microns (e.g., beads of polyalkyl methacrylate, silica, calcium carbonate, titanium dioxide, zein and the like).

A particularly valuable embodiment of this invention relates to a photographic element comprising a polyester support having, on one surface, a light-sensitive silver halide emulsion layer and a layer comprising vinylidene chloride, alkyl acrylate, itaconic acid copolymer, with the other surface of the support having (1) an antistatic layer, as described herein, and (2) a layer comprising vinylidene chloride, alkyl acrylate, itaconic acid copolymer'and having a coating weight in the range of about 0.05 to about 0.5 mg. of copolymer per square decimeter, said coating weight being no more than about 10%, by weight, of the coating weight of the copolymer layer on the other surface of the polyester support, and each of the copolymer layers being adjacent to the polyester support. It has been found that the photographic elements containing the copolymer subbing layers bearing this relationship exhibit significantly improved antistatic properties, in combination with good blocking and ferrotyping properties.

In practicing this invention the polyester film support is coated on each surface with a subbing composition latex comprising a vinylidene chloride, alkyl acrylate, itaconic acid copolymer. The subbing composition on the emulsion side surface of the polyester film support is coated as a relatively thick layer. The coating weight of the copolymer in this subbing layer is generally in the range of about 0.8 to about 5 mg., preferably about .8 to about 2 mg., of copolymer per square decimeter. The other layers of the photographic element such as the light-sensitive layer, antihalation layers, and the like, are coated over this relatively thick subbing layer. The vinylidene chloride, alkyl acrylate, itaconic acid copolymer is coated as a relatively thin subbing layer on the back of the polyester support. The coating weight of the copolymer in this layer is generally in the range of about 0.05 to about 0.5 mg. of copolymer per square decimeter, and this coating weight is no more than about by weight, of the coating weight of the copolymer layer on the other surface of the support. The antistatic composition described herein is then coated over this relatively thin layer and there is obtained a photographic element having exceptionally good resistance to blocking and ferrotyping, as shown in the following example.

As already indicated, a vinylidene chloride, alkyl acrylate, itaconic acid copolymer is employed in the subbing composition latex. The preferred copolymer comprises a copolymer of about 10 to about by weight, of an alkyl acrylate, about 80 to about 89%, by weight, of vinylidene chloride and about 1 to about 4%, by weight, of itaconic acid. A particularly useful material is a copolymer of about 15%, by weight, of methyl acrylate, 83%, by weight, of vinylidene chloride and 2%, by weight, of itaconic acid. For convenience of reference this composition will be referred to hereinafter as MaVcIt. Another useful subbing composition comprises a copolymer of acrylonitrile, acrylic acid and vinylidene chloride, and more particularly, a copolymer of about 10 to about 15%, by weight, of acrylonitrile, about 1 to about 12%, by weight, of acrylic acid, and the remainder to make a total of 100%, by weight, of vinylidene chloride.

Particularly advantageous subbing composition latices for carrying out this invention are formulated as follows:

By weight (percent) Water sufficient to make a total of 100% of latex.

It has been determined that 0.5%, by weight, of resin in the copolymer subbing layer under the antistatic layer is optimum for obtaining minimum blocking and ferrotyping defects when film is held in roll form. Thicker subbing or undercoat layers produce undesirable blocking and ferrotyping. The resorcinol is a base swelling agent and improves bonding while the Saponin improves spreading and uniformity of application. This subbing or undercoat is normally applied to the film base or support prior to drafting, tentering and heat setting to improve its bond to the film base or support.

In place of the resorcinol in the coating formulations, there can be substituted any other phenolic compound having the structural formula:

wherein R can be hydrogen; a lower alkyl radical of from about 1 to 6 carbon atoms, such as methyl, ethyl, propyl, n-butyl, and hexyl; a halogen such as chlorine, bromine, or iodine; or a hydroxyl radical. Specific examples of these compounds include pyrocatechol, pyrogallol, hydroquinone, orcinol, and chlororesorcinol.

Other suitable adhesion promoters that can be employed in carrying out this invention include trichloroacetic acid, ethylene carbonate, chloral hydrate (2,2,2- trichloro 1,1 ethanediol), chloro thymol, and ortho cresol. Mixtures of two or more of these adhesion promoters can be employed if desired.

The amount of the adhesion promoter employed can be varied over a relatively wide range. It has been determined, however, that from about 1.0 part, by weight, to 3.0 parts, by weight, of adhesion promoter based on one 4 part by weight of the MaVcIt resin produces satisfactory results.

In place of the Saponin in the subbing compositions, there can be substituted other suitable spreading agents including cetyl betaine, polyglycerol monolaurate, and the sodium salts of alkyl aryl sulfonates. The amount of spreading agent employed can be varied over a wide range and it is well within the skill of those versed in the art to incorporate into the composition the desired amount. Usually, the amount employed will vary from about 0.02 part, by weight, to 0.07 part, by weight, based on one part by weight of the MaVcIt resin employed in preparing the composition.

Further details as to the preparation of suitable subbing compositions and their application to polyester film supports can be had by reference to Nadeau et al., US. Patent No. 3,143,421; issued Aug. 4, 1964.

Suitable polyester film supports for use in carrying out this invention are highly polymeric linear polyesters of bifunctional aromatic dicarboxylic acids condensed with bifunctional polyhydroxy organic compounds. These are well known and can be prepared from any of the polyester compositions described in Nadeau et al. US. Patent No. 2,943,937; issued July 5, 1960, or in Alles et al. US. Patent No. 2,627,088; issued Feb. 3, 1953, or in Alles US. Patent No. 2,779,684; issued Jan. 29, 1957. In carrying out this invention it is preferred that the polyester film support be biaxially stretched prior to the application to a surface thereof of the antistatic coating composition of this invention. Methods of biaxially stretching polyester film to provide an oriented film are known in the art.

A specific example of a polyester film support that has proved highly satisfactory for use in preparing photographic film products in accordance with this invention is that prepared from an ethylene glycol-terephthalic acid polyester having a melting point above about 200 C. Polyesters of this type and their method of preparation are described in Whinfield et al. US. Patent No. 2,465,- 319, issued Mar. 22, 1949. Thus, the desired amounts of ethylene glycol and terephthalic acid are placed in a suitable reaction vessel and the polymerization is carried out under a vacuum of 0.5 mm. and at a temperature of from about 215 C. to about 285 C. A molten polyethylene terephthalate is prepared and is cast into a film of desired thickness usually of the order of from about 3 mils to about 7 mils.

The subbed and oriented polyester film support prepared as described above is then overcoated on the relatively thin subbed surface with the novel antistatic composition of this invention. This composition is applied in such concentration and manner known to the art as to give an antistatic layer on the film support not exceeding in dry condition about one micron and preferably from about 0.4 to about 1.0 micron in thickness.

Particularly suitable antistatic compositions for carrying out this invention are formulated as follows:

Percent by weight Polyvinyl alcohol 0.5-2 Cetyl betaine 0.05-0.50 Potassium chloride 0.l00.30

Polymethyl methacrylate matte 0.075-l.60 Zirconium nitrate 0.050.l0 Water sufficient to make a total of The chlorides have greater conductivity than, for instance, the nitrates or sulfates. Also, activity on the sensitive photographic emulsion is very slight with the chlorides. Potassium chloride shows lower hygroscopicity than the other alkali metal chlorides and is the preferred conducting chemical of this invention. This unique property is of advantage in preserving the photographic quality of films which can deteriorate badly when moisture is absorbed.

The cetyl betaine in the above formulation can be replaced with any other of the previously mentioned spreading agents, e.g., with saponin. The zirconium nitrate is present as a hardener for the polyvinyl alcohol. The concentration range of the polymethyl methacrylate matte or beads can vary from about 15 to about 150%, based on the weight of the polyvinyl alcohol. As already indicated, other matting agents, e.g., silica, etc., can be used in practicing this invention. Furthermore, other homopolymers or copolymers of alkyl methacrylates, particularly lower alkyl methacrylates, can be used (e.g., polyethyl methacrylate, copolymers of methyl methacrylate and ethyl methacrylate, polybutyl methacrylate, etc.). The matting agents employed in the practice of this invention generally have cross section diameters in the range of about 0.5 to about 15 microns. The above antistatic formulation can also be varied as to total solids content over a relatively wide range depending on the specific application, for example, from about 0.5 to about 5%, or even more for certain antistatic coating uses.

In connection with the preceding description of the novel antistatic compositions and preferred formulations thereof, 1 have found that, in order to obtain the outstanding results described herein, it is necessary to use polyvinyl alcohol as the binder or carrier in combination with the other components, and more particularly, with the preferred conducting chemical, potassium chloride. For example, polyvinyl alcohol has been found to have a definite advantage over gelatin as a carrier in that the use of other materials, e.g., gelatin, as the binder in the antistatic layers of this invention significantly increases block or ferrotype when brought into contact with the gelatin of the emulsion under tension in rolls. The polyvinyl alcohols employed in the practice of this invention include any of those materials which are generally used in photographic elements as binders. These polyvinyl alcohols are water soluble and generally have less than about 25%, usually less than about by weight, of residual acetyl content. The preferred polyvinyl alcohols are those having a residual acetyl content of 2%, or less.

For a more complete understanding of this invention, reference is made to the following detailed drawing, in which:

FIG. 1 shows a cross sectional view of a composite film made in accordance with this invention wherein a polyester film support 10 is coated with the novel antistatic layer 11.

FIG. 2 shows a cross sectional view of a photographic film element of this invention wherein the polyester film support 10 is coated on one side with the novel antistatic layer 11, and on the other side of the support with a suitable subbing layer 12 and thereover a light-sensitive silver halide emulsion layer 13.

FIG. 3 shows a cross sectional view of a photographic element according to one embodiment of this invention which comprises a polyester film support 10, an antistatic layer 11, a subbing layer 12, a light-sensitive layer 13 and, between the support and the antistatic layer, a thin subbing layer 14.

It will be understood that in the preferred form of the invention (not shown in FIG. 1 and FIG. 2) a suitable thin subbing layer 14 is employed to anchor antistatic layer 11 firmly to polyester film support 10, as shown in FIG. 3. Also, two or more subbing layers can be superimposed on one another on the emulsion side of the film element of FIG. 2. Suitable subbing layers for these purposes are described in Nadeau et al. US. Patent No. 3,143,421, issued Aug. 4, 1964. An antihalation layer can also be included, if desired, under the emulsion layer.

In practicing this invention, the composite film element, prepared as above described, and as depicted in the accompanying drawing as FIG. 1 is coated on the reverse side to the antistatic layer with a suitable subbing composition such as previously described. Over this is applied a gelatin layer which may also function as an antihalation layer. To the thus applied gelatin layer there is then applied a light-sensitive gelatinous silver halide emulsion layer to provide the highly satisfactory photographic film element of this invention depicted in the accompanying drawing as FIGS. 2 and 3.

As already indicated, the photographic elements of this invention exhibit improved properties such as improved antistatic, blocking and ferrotyping properties. This can be illustrated by the following Example in which the antistatic properties are reported as backing resistivity in ohms. Blocking data is obtained by stacking six one-foot lengths of 35-II1II1. film, one on top of the other, and placing a 15-lb. weight on the stack. The weight is removed after the samples have been held at 120 F., 60% relative humidity for 1 week. The strips are removed from one another and a Blocking Number, determined as an average on the six film strips, is assigned as follows:

Blocking number: Explanation 1 No adhesion. 2 Trace adhesion. 3 Very slight adhesion. 4 Slight adhesion. 5 Moderate adhesion. 6 Strong adhesion.

Ferrotype characteristics can be obtained by Winding a length of a 35-min. strip of film under constant tension on a spool and holding the wound sample at 120 F., 60% relative humidity for 1 week. The sample is then unwound and evaluated to determine the angle at which the free end of the film clings to the spool, i.e., the Clinging Angle. The lower the Clinging Angle the better the ferrotype characteristics of the film.

The invention is further illustrated by the following example.

EXAMPLE An extruded polyester film support of polyethylene terephthalate is coated by a roll applicator with a subbing composition made by intimately mixing 0.5%, by weight, of MaVcIt, 1.0%, by weight, of resorcinol, 0.25%, by weight, of saponin and 98.25%, by weight, of water. The MaVcIt is supplied as a 15% latex dispersion and the other components are incorporated therein. One side of the support is subbed at a coating weight of about 0.1 mg./dm. on the back and about 1.2 mg./dm. on the front surface; the front surface being the one over which the light-sensitive emulsion layer is to be coated.

Over the subbing layer, on the back of the polyester film support, after drying, is dip coated and air knife doctored an antistatic layer made by intimately mixing 0.66%, by weight, of polyvinyl alcohol (about 2% residual acetyl content), 0.10%, by weight of a 10% solution of cetyl betaine in water, 0.05%, by weight, of potassium chloride, 0.07%, by weight, of zirconium nitrate and Water. The pH of this solution is adjusted to 5.5 with a 4% aqueous sodium hydroxide solution. To this is added 0.3%, by weight, of polymethyl methacrylate beads. The beads are added as a 10%, by weight, dispersion in water. Water is then added to make a total of of the antistatic dispersion.

The subbed support is then coated on the front surface with an emulsion of silver halide dispersed in gelatin.

The light-sensitive photographic film element thus constructed shows superior properties in comparison to a film 7 element prepared using the same procedure but without an antistatic layer, i.e., Unbacked Film, as shown in the following table.

By inspection of the values shown in the above table, it will be seen that the antistatic layer backed film is manifestly superior in each of these tests. For example, the backing resistivity of the backed film is only about 35% that of the unbacked film indicating thereby superior conductivity of the backed film. The clinging angle and Blocking results also show decided advantages for the backed film in comparison with the unbacked film.

When gelatin is substituted for the polyvinyl alcohol in the above example, the light-sensitive photographic film element produced therewith has acceptable antistatic properties but it has a blocking value of 6 and a very poor clinging angle.

This invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinbefore and as defined in the appended claims.

I claim:

1. An antistatic composition comprising (a) a polyvinyl alcohol binder, (b) an alkali metal halide and (c) a matting agent having particles of cross section diameter in the range of about 0.5 to about 15 microns.

2. The antistatic composition of claim 1 in which the alkali metal halide is potassium chloride.

3. An antistatic composition comprising (a) a polyvinyl alcohol binder, (b) potassium chloride and (c) polymethyl methacrylate beads having a cross section diameter in the range of about 0.5 to about 15 microns.

4. The antistatic composition of claim 1 in which the matting agent is silica.

5. An antistatic composition consisting essentially of about 0.5 to about 2%, by weight, of polyvinyl alcohol binder, about 0.05 to about 0.5%, by weight, of cetyl betaine, about 0.1 to about 0.3%, by weight, of potassium chloride, about 0.075 to about 1.6%, by weight, of poly methyl methacrylate beads having a cross section diameter of about 0.5 to about 15 microns, about 0.05 to about 0.1%, by weight, of zirconium nitrate and sufficient water to make up a total of 100% of said composition.

6. An antistatic photographic film element comprising a polyester support having on at least one side thereof an outer layer of an antistatic composition of claim 1.

7. An antistatic photographic film element comprising a polyester support having on at least one side thereof an outer layer of an antistatic composition of claim 3.

8. An antistatic photographic film element comprising a polyester support having on at least one side thereof an outer layer of an antistatic composition of claim 4.

9. An antistatic photographic film element comprising a polyester support having on at least one side thereof an outer layer of an antistatic composition of claim 5.

10. An antistatic, light-sensitive photographic film element comprising a polyester support having a backing layer on one side of an antistatic composition of claim 1, and on the opposite side, at least one layer of a lightsensitive silver halide emulsion.

11. An antistatic, light-sensitive photographic film element comprising a polyester support having a backing layer on one side of an antistatic composition of claim 3, and on the opposite side, at least one layer of a lightscnsitivc silver halide emulsion.

12. An antistatic, light-sensitive photographic film element comprising a polyester support having a backing layer on one side of an antistatic composition of claim 4, and on the opposite side, at least one layer of a lightsensitive silver halide emulsion.

13. An antistatic, light-sensitive photographic film element comprising a polyester support having a backing layer on one side of an antistatic composition of claim 5, and on the opposite side, at least one layer of a lightsensitive silver halide emulsion.

14. A photographic element comprising a polyester support having on one surface a light-sensitive silver halide emulsion layer and a layer comprising vinylidene chloride, alkyl acrylate, itaconic acid copolymer, the other surface of said support having (1) an antistatic layer comprising polyvinyl alcohol binder, an alkali metal halide and a matting agent having particles of cross section diameter of about 0.5 to about 15 microns and (2) a layer comprising vinylidene chloride, alkyl acrylate, itaconic acid polymer and having a coating weight in the range of about 0.05 to about 0.5 mg. of copolymer per square decimeter, said coating weight being no more than about 10%, by weight, of the coating weight of the copolymer layer on the other surface of said support and each of said copolymer layers being adjacent to said support.

15. A photographic element comprising a polyester support having on one surface a light-sensitive silver halide emulsion layer and a layer comprising a copolymer of about to about 89%, by weight, vinylidene chloride, about 10 to about 15%, by weight, of an alkyl acrylate, and about 1 to about 4%, by weight, of itaconic acid, the other surface of said support having (1) an antistatic layer comprising polyvinyl alcohol binder, an alkali .metal halide and a matting agent having particles of cross section diameter of about 0.5 to about 15 microns and (2) a layer comprising a copolymer of about 80 to about 89%, by weight, of vinylidene chloride, about 10 to about 15%, by weight, alkyl acrylate and about 1 to about 4%, by weight, of itaconic acid and having a coating weight in the range of about 0.05 to about 0.5 mg. of copolymer per square decimeter, said coating weight being on more than about 10%, by weight, of the coating weight of the copolymer layer on the other surface of said support and each of said copolymer layers being adjacent to said support.

.16. A photographic element comprising a polyester support having on one surface a light-sensitive silver halide emulsion layer and a layer comprising a copolymer of about 80 to about 89%, by weight, vinylidene chloride, about 10 to about 15 by weight, of an alkyl acrylate and about 1 to about 4%, by weight, itaconic acid, the other surface of said support having (1) an antistatic layer comprising polyvinyl alcohol binder, an alkali metal halide and a matting agent having particles of cross section diameter of about 0.5 to about 15 microns, and (2) a layer comprising a copolymer of about 80 to about 89%, by weight, vinylidene chloride, about 10 to about 15 by weight, of an alkyl acrylate and about 1 to about 4%, by weight, of itaconic acid and having a coating weight in the range of about 0.05 to about 0.5 mg. of polymer per square decimeter, said coating weight being no more than about 10%, by weight, of the coating weight of the copolymer layer on the other surface of said support, which coating weight is in the range of about 0.8 to about 5 mg. of copolymer per square decimeter, each of said copolymer layers being adjacent to said support.

17. The photographic element of claim 16 in which the alkali metal halide is potassium chloride.

18. The photographic element of claim 16 in which the polyester support is polyethylene terephthalate, the alkali metal halide is potassium chloride and the matting agent is polymethyl methacrylate beads.

19. The photographic element of claim 16 in which the polyester support is polyethylene terephthalate, the

9 alkali metal halide is potassium chloride and the matting agent is silica.

20. A photographic element comprising a polyester support having on one surface a light-sensitive silver halide emulsion layer and a layer comprising vinylidene chloride, acrylonitrile, acrylic acid copolymer, the other surface of said support having 1) an antistatic layer comprising polyvinyl alcohol binder, an alkali metal halide and a matting agent having particles of cross-section diameter of about 0.5 to about 15 microns, and (2) a layer comprising vinylidene chloride, acrylonitrile, acrylic acid copolymer and having a coating weight in the range of about 0.05 to about 0.5 mg. of copolymer per square decimeter, said coating weight being no more than about 10%, by weight, of the coating weight of the copolymer layer on the other surface of said support and each of said copolymer layers being adjacent to said support References Cited UNITED STATES PATENTS Hoffman 106194 Lindquist 96--87 Patten 96--87 Morey 9687 Mackey 96-87 Nadeau et a1. 9687 Stevens 96-87 Vrancken et a1 96-87 NORMAN G. TORCHIN, Primary Examiner. R. H. SMITH, Assistant Examiner.

US. Cl. X.R. 

1. AN ANTISTATIC COMPOSITION COMPRISING (A) A POLYVINYL ALCOHOL BINDER, (B) AN ALKALI METAL HALIDE AND (C) A MATTING AGENT HAVING PARTICLES OF CROSS SECTION DIAMETER IN THE RANGE OF ABOUT 0.5 TO ABOUT 15 MICRONS. 